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Expose a file to a webpage with a Firefox extension

I have a web application that my client uses for the cash register. What I need to do is create a local file, because the cash register software must read from this file for printing. A.

So far I have used this code:

netscape.security.PrivilegeManager.enablePrivilege("UniversalXPConnect");
var file = Components.classes["@mozilla.org/file/local;1"].createInstance(Components.interfaces.nsILocalFile);
file.initWithPath(filePath);

Unfortunately, with the latest version of firefox, this no longer works, so I was told that I needed an add-in to create the file. I tried to develop an add-in (I don’t know if it is successful) and my main.js looks like this:

var FileManager =
{
Write:
    function (File, Text)
    {
        if (!File) return;
        const unicodeConverter = Components.classes["@mozilla.org/intl/scriptableunicodeconverter"]
            .createInstance(Components.interfaces.nsIScriptableUnicodeConverter);

        unicodeConverter.charset = "UTF-8";

        Text = unicodeConverter.ConvertFromUnicode(Text);
        const os = Components.classes["@mozilla.org/network/file-output-stream;1"]
          .createInstance(Components.interfaces.nsIFileOutputStream);
        os.init(File, 0x02 | 0x08 | 0x20, 0700, 0);
        os.write(Text, Text.length);
        os.close();
    },

Read:
    function (File)
    {
        if (!File) return;
        var res;

        const is = Components.classes["@mozilla.org/network/file-input-stream;1"]
            .createInstance(Components.interfaces.nsIFileInputStream);
        const sis = Components.classes["@mozilla.org/scriptableinputstream;1"]
            .createInstance(Components.interfaces.nsIScriptableInputStream);
        is.init(File, 0x01, 0400, null);
        sis.init(is);

        res = sis.read(sis.available());

        is.close();

        return res;
    },
};

Any ideas on how to use main.js? Where do I find it after installing the add-in? I need to use something like this: FileManager.Write (path, text).

+3
1

- .

, P.O.S, Firefox, - - HTTP. JavaScript .

, . Firefox, "" ( "" ) .

:

  • bootstrap.js( JavaScript, "" )
  • install.rdf( XML, FireFrox)

, ( !) ZIP .xpi. , about:addons, Install from file, XPI, , Install.

install.rdf - :

<?xml version="1.0"?>
<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#" 
     xmlns:em="http://www.mozilla.org/2004/em-rdf#">
    <Description about="urn:mozilla:install-manifest">
        <em:id>youraddonname@yourdomain</em:id>
        <em:type>2</em:type>
        <em:name>Name of your addon</em:name>
        <em:version>1.0</em:version>
        <em:bootstrap>true</em:bootstrap>
        <em:description>Describe your addon.</em:description>
        <em:creator>Your name</em:creator>

        <!-- Firefox Desktop -->
        <em:targetApplication>
            <Description>
                <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>
                <em:minVersion>4.0.*</em:minVersion>
                <em:maxVersion>29.0.*</em:maxVersion>
            </Description>
        </em:targetApplication>
    </Description>
</RDF>

JavaScript bootstrap.js:

  • startup() - .
  • shutdown() - .

startup(). (, , ) install() uninstall().

bootstrap.js:

const Cc = Components.classes;
const Ci = Components.interfaces;
let consoleService = Cc["@mozilla.org/consoleservice;1"]
                        .getService(Ci.nsIConsoleService);
let wm             = Cc["@mozilla.org/appshell/window-mediator;1"]
                        .getService(Ci.nsIWindowMediator);

function LOG(msg) {
  consoleService.logStringMessage("EXTENSION: "+msg);    
}

function startup() {
  try {
    LOG("starting up...");
    let windows = wm.getEnumerator("navigator:browser");
    while (windows.hasMoreElements()) {
      let chromeWindow = windows.getNext().QueryInterface(Ci.nsIDOMWindow);
      WindowListener.setupBrowserUI(chromeWindow);
    }
    wm.addListener(WindowListener);
    LOG("done startup.");
  } catch (e) {
    LOG("error starting up: "+e);
  }
}

function shutdown() {
  try {
    LOG("shutting down...");
    let windows = wm.getEnumerator("navigator:browser");
    while (windows.hasMoreElements()) {
      let chromeWindow = windows.getNext().QueryInterface(Ci.nsIDOMWindow);
      WindowListener.tearDownBrowserUI(chromeWindow);
    }
    wm.addListener(WindowListener);
    LOG("done shutdown.");
  } catch (e) {
    LOG("error shutting down: "+e);
  }
}

, WindowListener.setupBrowserUI() -. WindowListener :

var WindowListener = {
  setupBrowserUI: function(chromeWindow) {
    chromeWindow.gBrowser.addEventListener('load', my_load_handler, true);
  },
  tearDownBrowserUI: function(chromeWindow) {
    chromeWindow.gBrowser.removeEventListener('load', my_load_handler, true);
  },
  onOpenWindow: function(xulWindow) {
    let chromeWindow = xulWindow.QueryInterface(Ci.nsIInterfaceRequestor)
                         .getInterface(Ci.nsIDOMWindow);
    chromeWindow.addEventListener("load", function listener() {
      chromeWindow.removeEventListener("load", listener, false);
      var domDocument = chromeWindow.document.documentElement;
      var windowType = domDocument.getAttribute("windowtype");
      if (windowType == "navigator:browser")
        WindowListener.setupBrowserUI(chromeWindow);
    }, false);
  },
  onCloseWindow: function(chromeWindow) { },
  onWindowTitleChange: function(chromeWindow, newTitle) { }
};

OpenWindow , , load TabBrowser ChromeWindow. load :

var my_load_handler = function (evt) {
  try {
    var browserEnumerator = wm.getEnumerator("navigator:browser");
    while (browserEnumerator.hasMoreElements()) {
      var browserWin = browserEnumerator.getNext();
      var tabbrowser = browserWin.gBrowser;
      var numTabs = tabbrowser.browsers.length;
      for (var index = 0; index < numTabs; index++) {
        var currentBrowser = tabbrowser.getBrowserAtIndex(index);
        var domWindow = currentBrowser.contentWindow.wrappedJSObject;
        // identify your target page(s)...
        if (domWindow.location.href == 'http://yourserver/yourpage') {
          // install the privileged methods (if not already there)
          if (!domWindow.hasOwnProperty('__my_priv_members__') {
            install_my_privileged_methods(browserWin, domWindow);
          }
        }
      }
    }
  } catch (e) {
    LOG(e);
  }
}

( window.location.href install_my_privileged_methods window, :

function install_my_privileged_methods(chromeWindow, domWindow) {
  install_privileged_method(chromeWindow, domWindow, 'WriteFile', 
    function(priv) {
      return function(File, Text, cb) {
        priv.call([File, Text], function(rstatus, rdata, rerror){
          if (cb) cb(rstatus, rerror);
        });
      };
    },
    function (chromeWindow, args, cb) {
      var [File, Text] = args;
      if (!File) return cb(0, null, "need a filename");
      try {
        const unicodeConverter = 
           Cc["@mozilla.org/intl/scriptableunicodeconverter"]
             .createInstance(Ci.nsIScriptableUnicodeConverter);
        unicodeConverter.charset = "UTF-8";
        Text = unicodeConverter.ConvertFromUnicode(Text);
        const os = Cc["@mozilla.org/network/file-output-stream;1"]
                     .createInstance(Ci.nsIFileOutputStream);
        os.init(File, 0x02 | 0x08 | 0x20, 0700, 0);
        os.write(Text, Text.length);
        os.close();
        cb(1, null, null);
      } catch (e) {
        cb(0, null, "error writing file: "+e);
      }
    }
  );

  install_privileged_method(chromeWindow, domWindow, 'ReadFile', 
    function(priv) {
      return function(File, cb) {
        priv.call([File], function(rstatus, rdata, rerror){
          if (cb) cb(rstatus, rdata, rerror);
        });
      };
    },
    function (chromeWindow, args, cb) {
      var [File] = args;
      if (!File) return cb(0, null, "need a filename");
      try {
        const is = Cc["@mozilla.org/network/file-input-stream;1"]
                     .createInstance(Ci.nsIFileInputStream);
        const sis = Cc["@mozilla.org/scriptableinputstream;1"]
                      .createInstance(Ci.nsIScriptableInputStream);
        is.init(File, 0x01, 0400, null);
        sis.init(is);
        var Text = sis.read(sis.available());    
        is.close();
        cb(1, Text, null);
      } catch (e) {
        cb(0, null, "error reading file: "+e);
      }
    }
  );
}

. , ... , !

WriteFile ReadFile window. - () JavaScript- :

var buffer = '...'; // the text to be written
window.WriteFile('C:\\path\\to\\file.txt', buffer, function(ok, errmsg) {
  if (!ok) alert(errmsg);
});

window.ReadFile('C:\\path\\to\\file.txt', function(ok, buffer, errmsg) { 
  if (!ok) return alert(errmsg);
  // use buffer here!
});

, install_privileged_method :

var install_privileged_method = (function(){
  var gensym = (function (){
    var __sym = 0;
    return function () { return '__sym_'+(__sym++); }
  })();
  return function (chromeWindow, target, slot, handler, methodFactory) {
    try {
      target.__pmcache__ = target.hasOwnProperty('__pmcache__')
        ? target.__pmcache__
        : { ticket_no: 0, callbacks: {}, namespace: gensym() };
      target[slot] = methodFactory({ call: function(fargs, fcb) {
        try {
          var ticket_no = target.__pmcache__.ticket_no++;
          target.__pmcache__.callbacks[ticket_no] = fcb;
          var cevent = target.document.createEvent("CustomEvent");
          cevent.initCustomEvent(
            target.__pmcache__.namespace+'.'+slot,
            true, true, { fargs: fargs, ticket_no: ticket_no }
          );
          target.dispatchEvent(cevent);
        } catch (ue) {
          fcb(0, null, 'untrusted dispatcher error: '+ue);
        }
      }});
      LOG("installed untrusted dispatcher for method '"+slot+"'.");
      target.addEventListener(
        target.__pmcache__.namespace+'.'+slot,
        function(cevent){
          var ticket_no = cevent.detail.ticket_no;
          var fargs = cevent.detail.fargs;
          var fcb = target.__pmcache__.callbacks[ticket_no];
          try {
            handler(chromeWindow, fargs, fcb);
          } catch (pe) {
            fcb(0, null, 'privileged handler error: '+pe);
          }
        },
        false,
        true
      );
      LOG("installed privileged handler for method '"+slot+"'.");
    } catch (ie) {
      LOG("ERROR installing handler/factory for privileged "+
          "method '"+slot+"': "+ie);
    }
  };
})();
+1

Source: https://habr.com/ru/post/1539224/

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